Electric spark-gap.



H. BOAS.

ELECTRIC SPARK GAP.

APPLICATION FILED OCT-22,1912.

Patented Aug. 31, 1915.

E/ecfmde lVa/dar 1 2 v mdes J d a m 0 HANS BOAS, 0F BERLIN, GERMANV.

ELECTRIC SPARK-GAP.

Specification of Letters Patent.

Patented Aug. 31, 1915.

Application filed October 22, 1912. Serial No. 727,247.

T 0 all whom it may concern Be it known that I, HANS Boris, of Berlin,

a subject of the King of Prussia, and residing at 52 Krautstrasse,Berlin, Kingdom of Prussia, German Empire, have lnvented a new anduseful Electric Spark-Gap, of which the following is a specification.

It is known by the experimental work of Tesla that a spark gapconsisting of a large number of single spark gaps with very smalldistance between the electrodes is very useful in producing electricoscillations. Wlen has found that the reason for this fact is the largedamping action on the electric v1brations, and that by coupling in acertain man nor the circuit containing the spark gaps with a secondarycircuit having capacity and self-induction, a transfer of electrlcalenergy can be effected in the same manner as it is effected by excitingthe secondary circuit by the primary by one impact only. On thisprinciple is also based the spark gap of Lepel who uses flat plates ofmetal arranged a small distance from each other.

The large plate was intended to exert a cooling eifect on the spark, andfor this reason he and others have used plates of silver or copper. Withthese spark gaps a coupling up to 19.5% could be obtained as degreeof'much upon the kind of the material used for the electrode. For instanceusing silver or copper-electrodes a distance smaller than 0.01 mm. isimpracticable because these electrodes melt together by the heat of thesparks. With electrodes of platina-iridium a much smaller distance canbe used, less than the half,'because the pIatina i-ridium by reason ofits hi h melting point and its me chanical strengt opposes a much larerresistance to the melting by the heat of the spark. The platina-iridium,however, has certain disadvantages. It is relatively easily evaporated,and this evaporation alters the distanceof the electrodes. In the sparkgap itself there is much metal vapor exerting a disturbing effect on theaction of the spark gap. Y M

I have now found that tungsten is a ma' terial which is better suitedfor the con;

struction of spark gaps than any other material. The tungsten isunmeltable at the temperatures which can arise and is not liable to bedestroyed by being atomized into minute articles, which form a kind of adust,

and dissolve into spray. The consequence is that two electrodes of.tungsten can be adjusted at very much smaller distances without dangerof a short-circuit by the melting of the electrodes. With the tungstenthere is practically no spraying action and there:

fore no vapor in the spark gap. The elec-- trodes are practicallyindestructible so that' the distances of the electrodes once determinedare nearly continually maintained. The use of tungsten permits of afurther reduction of the diameter of the electrodes. The spark betweenthe tungsten electrodes is nearly noiseless and-has no tendency tosurpass the edges of the electrode, the consequence being that withaspark gap having tungsten electrodes practically pure sounds areproduced. Even ,if there is a wrong coupling between the primary andsecondary circuit there is no essentia/l alteration-of the sparksbetween the electrodes so that the wrong coupling has no disadvantageousin: fluence on the spark gaps of tungsten. These excellent qualitieswhich are peculiar to spark gaps having electrodes of tungsten.

allow, without p'rejudicing the operation, the

obtaining of critical coupling degrees of more than 45% between theprimary and secondary circuit. It may be. said that the tungsten air gapis a-source of energy for producing the vibrations of high frequencythat are substantially perfect, and which were not known heretofore.

I have. illustrated in the accompanying drawings a quen chedspark gapwith tungsten electrodes embodying mydnvention.

In a sim' ar way as tungsten tantalum .and molybdenum may be used forthe shine purpose;

What I do -eleim as my invention,- and desire to secure'by LettersPatent of the United 5 States, is

1. In quenched sparkgaps for producing I quickly'quenched vibrations, anelectrode consisting of tungsten. 2. In quenched spark gaps forproducing .IIGSSGS.

uenched vibrations, electrodes con- 0 1 l HANS BOAS. Witnesses HENRYHASPEB, Y WOLDEMAR

